Accuracy of two optical dendrometers for non destructive determination of woody biomass

Abstract

The objective of this study was to improve existing methods for determination of stem biomass in a non-destructive way, and verify the influence that laser dendrometers have on the prediction by existing empirical models in forest environment on the individual trees. This study was developed in Itatinga, SP, Brazil, in three plots of a Eucalyptus grandis plantation, totalizing 175 trees. The stem diameter of standing trees were measured with two dendrometers, Criterion and RC3H, along the stem up to 8 meters height. After the volume evaluation of standing trees they were felled and the diameter obtained with a caliper and a tape in the same positions in which the non-destructive measures were taken. Wood disks were removed and dried for determination of humidity. The determination of biomass was performed by volumetric and gravimetric technique using three different methods (traditional wood volume evaluation, Criterion and RC3H). Some models were tested for these techniques and the best adjustment was selected. In general, all models showed good adjustments. The standard error average of prediction for these models were overestimated in 1% with the traditional wood volume evaluation and underestimated in approximately 11% using the Criterion and 40% using the RC3H.

doi: 10.4336/2012.pfb.32.70.23